Connie Britton from the ABC series 'Nashville' poses for a portrait. AP photo.

NASHVILLE — Buddy Miller says these days it’s not unusual for duet partners to cut their love songs syllable by syllable while never even seeing each other: “In this town especially that’s what happens.”

That’s why the veteran Music City producer and band leader was so astounded by what he witnessed in the early days of working on the music for the television show “Nashville.” He was nervous about his session with Clare Bowen and Sam Palladio because their song “If I Didn’t Know Better,” written by John Paul White of The Civil Wars and Arum Rae, was challenging and served as a pivotal moment in the pilot. It had to be right, and that depended on the young actors being able to pull it off.

“They didn’t know they didn’t have to memorize the song or look each other in the eyes when you’re singing a love song,” Miller said. “For those two who’d never sung in a studio before to go in there, look each other in the eyes with the song memorized and sing the song, I had goose bumps and so did everybody else in the room. ... That had a whole lot more soul in it than most of the stuff that gets cut in this town.”

The music of “Nasvhille” has been as much a star on the hourlong ABC drama as Connie Britton, Hayden Panettiere, Charles Esten, Jonathan Jackson, Bowen and Palladio. Yes, each really does sing his or her own part, and so far fans seem to be responding, buying more than 800,000 digital singles. Panettiere’s “Telescope” has even cracked top 40 at country radio. The show’s soundtrack will be released by Big Machine Records this week.

The actors say they pay as much attention to the music as their lines. T Bone Burnett, husband of show creator Callie Khouri, oversees the music on the show and has signed up veteran producers and songwriting friends like White and Civil Wars partner Joy Williams and Elvis Costello, to name just a few, and set up a live band of trusted players. Each song is shaped in the studio before it’s taped for television.

“They’re like little plants and they’re all very well taken care of by the right people,” Bowen said.

Choosing the right songs has been a lot like choosing the right dialogue or location. Miller said each becomes a part of the character’s story, helping to push the narrative along. For Bowen and Palladio, who play the aspiring — and mutually infatuated — singers Scarlett and Gunner, the key moment was “If I Didn’t Know Better.”

For stars Britton and Panettiere, who play rivals country divas Rayna and Juliette, the key moment came a few weeks ago when they took the stage at Ryman Auditorium for their own duet, “Wrong Song.” After weeks of spiteful relations, the two temporarily put aside their differences and the song served as a touchstone for both disgruntled characters.

Miller calls Britton’s performance “fierce” and the 45-year-old actress says moments like those were the reason she chose to pursue the part.

“Once you hit 40 you sort of feel like you’re sort of set in your ways and kind of know what you’re good at,” Britton said. Taking a risk and going beyond her comfort zone brought a lot of challenges and fear, she said. “But it’s also good to know you can always throw yourself something new and at the end of the day, at least for me, when I really stretch is when I feel alive and really feel the rewards of that hard work.”

Most of the actors had some background in musical performance, but it’s been years since Britton gave up singing to focus solely on acting. Her performances have been a revelation for fans and critics alike, and her peers are repeatedly astounded.

“Just because somebody’s an actress doesn’t mean they’re a rock star, but she’s doing it,” Bowen said. “Like the scene at the Ryman, she’s a rock star. She’s amazing and she’s just pulling things that we are like, ‘Where did you get that from? That’s beautiful.’ And I think she’s got the most challenging job. The show is on her shoulders and she’s blazing the most amazing trail for it.”

Like Miller, Palladio uses the word fierce to describe Britton: “She’s just got a lot of strings to her bow. To come from ‘Friday Night Lights’ to ‘American Horror Story’ to then ‘Nashville’ is just such a leap. It shows her versatility, I think.”

Britton started the transformation by working with voice coach Valerie Morehouse and aims much of the credit for the show’s musical success and her own metamorphosis at Burnett. She called the Grammy- and Oscar-winning producer “a completely generous artist.”

“I think the reason why so many people want to work with him is because he has this amazing ability to challenge me and at the same time make me feel completely safe and excited to take risks,” Britton said. “He has the ability to bring out your true voice. I just feel so fortunate to have had the opportunity to have done that.”